Using an Adafruit Pro Trinket 5V, we cannot run more than maybe 255 LEDs when two APA102C strips (288 LEDs in total) are connected. Is this a memory limit of our microcontroller or some FastLED functions that allow only 255 LEDs addressed? It happens with all sketches from the developers which have been modified but very little, not adding many bytes, really.
Any hints what to look for?
it shouldn’t be a limit - without seeing your code it’s hard to tell if you have anything in your code that’s limiting to 255 leds on output, but there shouldn’t be anything in the library limiting the number of leds beyond ram - with 2k, you should be able to have over 600 leds, though that leaves you very tight on ram for anything else. Also you don’t mention what version of the fastled library you’re using.
@Andreas_Hopf - The problem that you might be having is when someone defines a variable with uint8_t. I often define a variable with uint8_t. This limits the variable to a maximum of 255. All of my projects have less than 255 LEDs until recently. So, there is no problem. When I recently got a 16X16 matrix, I started having problems since there were now 256 LEDs. The solution was to change the uint8_t to uint16_t which allows you to go as high as 65535. I just changed the code you were testing to take this into account. Also, you can also try the following code to test to see if you can run 288 LEDS but change line 9 NUM_LEDS from “8” to the number of LEDS in your strip:
https://gist.github.com/chemdoc77/52ded62fc801247cc648b1eb84f9d2ca
@Daniel_Garcia @Ken_White Thanks Daniel, we used the latest version of FastLED. What Ken wrote just below seems to make sense (8 bit integer variable unsuitable for numbers higher than 255). We’ll try it out over the weekend latest. In the very end, we want to have a long 432 LED strip (3 x APA102C) down a column in our living room; an alternative to the tried and trusted disco ball ; ) Thanks to both of you!